The present invention pertains to imide and arylene sulfide polymers and to methods for preparing imide and arylene sulfide polymers and more particularly pertains to methods for the preparation of aromatic imide sulfide polymers and to aromatic imide sulfide polymers.
Poly(phenylene sulfide), also referred to herein as "PPS", is an important commercial polymer with good thermal stability, good flame resistance, and good solvent resistance. Owing to its regular, linear structure and low glass transition temperature, also referred to herein as T.sub.g, of about 88 degrees C., PPS readily crystallizes. The low T.sub.g of PPS is detrimental in many desired high temperature applications. PPS is soluble in only a very limited number of solvents and only at elevated temperatures, generally above 200.degree.-250.degree. C. Some applications of PPS take advantage of this chemical resistance, for example in lining pipes and tubes which carry organic solvents or caustic liquids. It would be highly advantageous for other applications, however, to have PPS copolymers which are soluble in common organic solvents at room temperatures or at temperatures between room temperature and 200.degree. C. This would permit, for example, the casting or spin-coating of films of controlled thickness onto various substrates from solution using standard coating technology.
U.S. Pat. No. 4,786,713 to Rule, M. et al discloses a method for producing copoly(arylene sulfide-disulfide) by reacting a mixture of a diiodoaromatic compound and elemental sulfur. U.S. Pat. No. 4,792,600 to Rule, M. et al discloses a similar process utilizing a catalytic amount of an aromatic nitro compound. U.S. Pat. No. 4,794,162 to Ostlinning et al discloses a method for the preparation of high molecular weight polyarylene sulfides from low molecular weight polyarylene sulfides by a reaction with elemental sulfur. PCT Published Application No. WO 90/02149 by Rule, M. et al discloses a method for producing a copolymer of diphenyl ether and arylene sulfide by reacting diiododiphenyl ether, diiodobenzene and sulfur.
Polyimides, which are perhaps the most widely used of the thermally stable polymers, are, with some exceptions, non-crystalline and not melt processable due to very high glass transition temperatures. Polyimides are most commonly formed from imide precursor such as polyamic acids and are cyclized by thermal treatment after solvent processing. U.S. Pat Nos. 4,716,216 and 4,599,396, both to Takekoshi et al., disclose crystalline polyimides and polyetherimides containing phenylene sulfide units produced by reacting oligomers of phenylene sulfide having amino end groups and aromatic tetracarboxylic acid or its functional derivatives or bisimides, including halophenyl bisimides, disclosed in U.S. Pat. No. 4,578,470 to Takekoshi et al. This method provides crystalline polymers having alternating imide and phenylene sulfide groups. A shortcoming of this method is the requirement of preformed diamino phenylene sulfide oligomers.
It is therefore highly desirable to provide improved aromatic imide sulfide polymers and improved methods for the preparation of aromatic imide sulfide polymers.
It is also highly desirable to provide improved aromatic imide sulfide polymers and improved methods for the preparation of aromatic imide sulfide polymers, which provide high glass transition temperatures.
It is also highly desirable to provide improved aromatic imide sulfide polymers and improved methods for the preparation of aromatic imide sulfide polymers, which do not require preformed terminally functional arylene sulfide oligomers.
It is finally highly desirable to provide improved aromatic imide sulfide polymers and improved methods for the preparation of aromatic imide sulfide polymers, which provide all of the above desired features.